Colonoscopy is a procedure that examines the large bowel or colon. This area is highlighted in yellow on the diagram.

A colonoscopy may be done to investigate symptoms such as abdominal pain, diarrhoea, change in bowel pattern, bleeding, weight loss or abnormal test results. It allows doctors to detect and remove polyps, biopsy inflamed tissue or identify colorectal cancers.

The procedure involves passing a flexible tube into the bottom and around the colon. This may be somewhat uncomfortable so it is normally done while you are sedated.

The colon must be emptied out of waste matter. You will be provided with instructions on how to modify your diet and what laxative drinks to take in preparation for the test. Follow these instructions carefully and expect to experience lots of diarrhoea. If the bowel is not completely clean and empty, the procedure may need to be postponed or repeated or lesions such a polyps or cancers may be missed.

Some medications may need to be stopped for up to a week before the procedure. These might include iron tablets, blood thinners, anti-platelet medications or diabetic medications. If you are unsure about whether you need to stop medications before your test, please clarify with your doctor well before the date.

A bowel polyp is an abnormal growth of tissue on the bowel wall. A polyp may turn into bowel cancer after many years of growing. It may be detected during a colonoscopy and can usually be removed safely and completely during the procedure. During the test, your doctor can also take biopsies if necessary.

Although complications during this procedure can occur, they are very uncommon. Driving is not permitted for 24 hours after the procedure, to allow all the sedation medication to wear off. You will need someone to stay with you at home the night after the procedure.